EP0162821A1 - Method and apparatus for measuring the level of a fluent material in a container - Google Patents
Method and apparatus for measuring the level of a fluent material in a container Download PDFInfo
- Publication number
- EP0162821A1 EP0162821A1 EP85850132A EP85850132A EP0162821A1 EP 0162821 A1 EP0162821 A1 EP 0162821A1 EP 85850132 A EP85850132 A EP 85850132A EP 85850132 A EP85850132 A EP 85850132A EP 0162821 A1 EP0162821 A1 EP 0162821A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- waveguide
- signal
- mode
- level
- container
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000463 material Substances 0.000 title claims abstract description 24
- 238000000034 method Methods 0.000 title claims abstract description 11
- 238000012545 processing Methods 0.000 claims abstract description 3
- 239000004020 conductor Substances 0.000 claims description 6
- 238000013016 damping Methods 0.000 description 9
- 239000007788 liquid Substances 0.000 description 6
- 239000003921 oil Substances 0.000 description 5
- 230000005855 radiation Effects 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 239000010779 crude oil Substances 0.000 description 2
- 238000002592 echocardiography Methods 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000001902 propagating effect Effects 0.000 description 2
- 238000007634 remodeling Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
- B04B—CENTRIFUGES
- B04B3/00—Centrifuges with rotary bowls in which solid particles or bodies become separated by centrifugal force and simultaneous sifting or filtering
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
- G01F23/22—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water
- G01F23/28—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water by measuring the variations of parameters of electromagnetic or acoustic waves applied directly to the liquid or fluent solid material
- G01F23/284—Electromagnetic waves
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
- G01S13/06—Systems determining position data of a target
- G01S13/08—Systems for measuring distance only
Abstract
Description
- This invention relates to a method for measuring the level of a fluent material stored in a container by means of a microwave signal which is fed out of a transmitter through a tubular waveguide that extends vertically downwardly through the container and so communicates with it that the surface of the material in the waveguide follows the level of the surrounding material, and which signal is reflected by the surface back up through the waveguide and is conducted to a receiver, to be employed, after signal processing in an electronic unit, for determining the level of material in the container. The invention also relates to apparatus for practicing this method.
- Radar can be employed for measuring the level of a liquid or liquid-like material that is contained in a cistern, tank or the like, as described for example in U.S. Patent No. 4,044,355. Because the velocity of radar waves in air or other gases is very stable, a good accuracy is obtained, and because the radar antenna can be made of very durable material, such a level measurer can be employed in environments that are very extreme with respect to temperature, chemical corrosion and mechanical stress. Since the radar antenna can be mounted in a hole in the top of the tank, its installation becomes simple and it also becomes simple to perform maintenance and eventual replacement.
- It has heretofore been a limitation on its employment that a radar beam requires a certain space among the existing struts, ladders, pipes, etc. in the tank. If a round radar antenna with a diameter D is employed, the usable width of the radar beam becomes about a/D radian but the undisturbed zone taking into consideration the diffuse boundaries of the radar beam, must be a cone with a top angle of about 2 λ/D radians. Here, A designates the wavelength of the radar carrier wave, which can be, for example, 3 cm. On the basis of various practical considerations the antenna-diameter must be held within certain limits and the wavelength of the carrier wave is in practice limited downwardly inasmuch as the radar transmitter and other components become expensive and critical in various respects with very high carrier frequency. Thus the radar beam cannot be arbitrarily narrow, and in several applications this is not at all desirable, for example when the apparatus is employed in a tanker ship with varying trim and list. In a practical case an angle of 5 - 15° can be mentioned as a typical space requirement, and this means that many tanks do not allow a radar level measurer with free space propagation to be installed. This applies no less to cisterns or tanks with so-called floating roofs, that is to say, tanks with roofs that float directly upon the contents.
- A method for avoiding the above mentioned limitation is to guide the radar waves in a waveguide that extends downwardly through the tank. Level measuring according to this method has heretofore been tried (see for example U.S. Patent No. 4,359,908) but has great practical limitations owing to the fact that a normal waveguide has a relatively small diameter, in order to be suitable for the radar frequency range to be employed. The waveguides that are referred to have comprised rectangular or circular cylindrical pipes of metal with dimensions that allow one-mode propagation. For a circular waveguide this implies that the wavelength A should be between 1.3 and 1.7 times the inside diameter of the pipe, and for typical radar frequencies the pipe diameter thus has a magnitude on the order of only a few centimeters.
- Such a waveguide presents these problems:
- If the tank contents is crude oil rich in wax, the pipe becomes clogged.
- The propagation of the radar waves is unacceptably influenced by the hole in the tubular waveguide that is needed for assuring free flow of liquid between the outside and the inside.
- Corrosion in the pipe causes unacceptable damping in transmission from top to bottom with normally occurring tank heights. It therefore becomes necessary to make the pipe of expensive material or to coat its inside with noble metal.
- The speed of propagation is powerfully influenced by the pipe dimension and the radar frequency and a good accuracy therefore imposes a very strong requirement for these magnitudes to be constant or accurately known.
- The present invention proceeds from the realization that these problems can be solved by employing a powerfully overdimensioned waveguide to which radar radiation is so conducted that all undesired waveguide modes are suppressed. The waveguide, in the majority of practical cases, can be assumed to consist of an existing pipe in the cistern or tank, which means that a useful construction must be able to tolerate substantial variations of the dimensions of the pipe from case to case. It is also necessary that a reasonable mass of rust and oil coating be acceptable.
- A pair of calculations of practical cases can illustrate the significance of employing the overdimensioned circular waveguide. If the distance is measured through the waveguide, there is obtained an apparent distance L that is greater than the real distance L, and the quotient can be expressed by the formula
- For a normal waveguide with one-mode propagation the factor is typically 2/3. For measuring with crude oil there is required a measuring accuracy of about 10-4 which means a maximum error of 2 mm in a 20 m distance, and the same accuracy would then be required of the pipe diameter and frequency, which is not practically possible. If, instead, one employs a pipe with for example a 25 cm diameter and a wavelength of 3 cm., the factor sinks to 5/1000. There is thus obtained a relative accuracy of 10-4, provided that the accuracy of diameter and of frequency are on the order of one percent, which is reasonable.
- Damping in a waveguide depends upon the resistive loss in the walls, and the calculation thereof is found in several handbooks about waveguides, for example Marcuvicz: "Waveguide Handbook," McGraw Hill, 1951. For a one-mode waveguide of copper, the diameter of which is about 2 cm, with /\= 3 cm., the damping through a 25 m long waveguide forwardly and rearwardly is about 10 dB. If stainless steel is employed the damping becomes about 10 times higher (about 100 dB), which is too much to permit accurate level measuring.
- If signals of the same wavelength are instead led through a pipe with for example a diameter of 25 cm, the damping becomes 40 times lower, and even with a steel pipe the damping then stands at 2.5 dB. In practice the damping will become larger by reason of an oil deposit on the inside of the pipe, but the low damping in the ideal case allows a sufficient margin for deterioration in operation.
- The reason for the damping decreasing when the pipe diameter is increased is, as is known, that the surface current on the walls decreases, with a similarly large transferred power in the waveguide. For the same reason, therefore, significantly more holes can be tolerated in the envelope surface of a very large pipe than would be permitted in a waveguide with normal diameter.
- In prior reasoning it has been accepted to employ the basic mode of the waveguide, that is, H11 according to the designation system in the above mentioned handbook. To improve tolerance to the influence of rusty walls, holes and the like, it would however be preferable to employ the H 01 propagation mode, which yields a significantly lower current in the walls of the waveguide and thereby lower losses. In addition to the low losses, an important characteristic of the H01 mode is that all current in the wall of the pipe flows in the peripheral direction, so that disturbances from existing pipe joints are insignificant.
- For obtaining an accurate distance measurement in a pipe in accordance with the present inventive idea, it is necessary that all undesired propagation modes be suppressed. If that is not the case, a normal echo will be interpreted as plural echoes from different distances, because the different propagation modes in general have different speeds in the pipe. A typical demand upon power overweight for the desired mode can be 25 dB, and this presents a large demand upon the measurement apparatus in the upper end of the pipe.
- The demand is in part that the emission energy in the undesired modes be sufficiently low, in part that the sensitivity for incoming power in undesired modes be sufficiently low. This latter demand must be posed to avoid having the power reach the receiver that is spread to undesired modes by way of holes in the pipe walls.
- The object of the present invention is to provide a method and apparatus for accurately determining with radar the level of a liquid or other fluent material that is held in a container. In this the invention especially aims to solve the above discussed problemsthat arise when a pipe extending through the container is to be employed as a waveguide. For application of the method to tanks or cisterns on land, comprising so-called floating roofs, it is in this respect a special objective to have a simple installation of radar apparatus that does not make necessary extensive and expensive remodeling of the tank or the cistern.
- This objective is achieved according to the invention because the method and apparatus have the characteristics set forth in the patent claims below.
- The invention will now be described in detail with reference to the accompanying drawings, which show an exemplary embodiment and in which:
- Fig. 1 is a vertical section of an oil cistern of a type that provides an important application for the invention;
- Fig. 2 shows a vertical section through a mode generator according to the invention and the upper portion of a pipe used as a waveguide extending into the cistern in Fig. 1;
- Fig. 3 is a top view of a mode filter comprising a part of the apparatus of Fig. 2;
- Fig. 4 is a bottom view of a reflector also comprising a part of the apparatus of Fig. 2; and
- Fig. 5 is a view in section taken along the line V-V in Fig. 4.
- The application of the invention that is illustrated in Fig. 1 is for carrying out level measuring in a
cistern 1 that can be built up on a foundation on theground 2 and wherein there can be stored a large quantity of oil or otherfluent material 3 which, while in storage, is protected by a so-calledfloating roof 4. Such a cistern can be very large, with a diameter on the order of 100 m; and because every millimeter of height represents a substantial volume and a large economic worth, it is required that the level of material shall be measured exactly, for determining the contents of the tank as correctly as possible. - At the top of the cistern there is a
platform 5 to which leads astairs 6 and to which is fixed the upper end of apipe 7 provided for level measuring. Through anopening 8 in thefloating roof 4 thepipe 7 extends vertically downward to the bottom of the cistern, where it is fixed. Along the whole of its length the pipe is perforated with sufficiently large and closely spacedholes 9 so that the interior of the pipe is communicated outwardly and theliquid surface 10 in the pipe can follow the level of the surrounding liquid, that is, the underside of theroof 4, see Fig. 2. A similar pipe in existing tanks was originally intended for housing a float belonging to a mechanical measuring device and its diameter is therefore usually as opportunely large as 20 to 30 cm. - It will be appreciated that it is of great value if, in converting to a radar measuring system with such a storage structure, the installation can be based upon the existing cistern construction and, with this, also continue to employ the large pipe that had been provided for float measuring. A remodeling of an oil cistern of the size here suggested with a view to instead base a radar measuring system upon a free antenna radiation would involve such large costs and be so hard to carry out, especially if the cistern had a floating roof, that it would not be a realistic alternative.
- The solution that the invention contemplates to the problem of providing a measuring system that can be installed in cisterns so that they can maintain a performance as set forth above principally involves employing the
cistern pipe 7 as a waveguide and feeding it with a microwave signal by a mode generator generally designated by 11, which is applied to the pipe and is arranged to produce only one dominant mode of propagation of the signal. - In the illustrated example the mode generator comprises a
cylindrical waveguide 12 which is coupled by means of a coaxial conductor 13 to a transmitter (not shown) that is included in an electronic unit which is suitably mounted in ahousing 14 above theplatform 5. Thewaveguide 12 should have such a diameter in relation to the wavelength of the supplied signal that only modes H11 and E01 can be transmitted, and with the help of sym- metry it can be brought about that only the latter mode will be found in the signal. The waveguide passes over into a downwardly directedprimary radiator 15 which can be formed as an antenna horn and which produces an antenna beam with for example a 60° lobe width and a field image of E01 character so that the electrical field is radially directed. - The mode generator in the illustrated example is of the double reflector type and here comprises two
reflectors conductors 18, preferably produced as a printed pattern of leads. The mutual distance between the conductors should be so small that the E01 mode emitted from theantenna horn 15 is reflected, in the main, just as well as in a continuous metal surface. - The
second reflector 17, which in the example is supported by ametal pipe 19 that constitutes an upward elongation of thecistern pipe 7, should have a parabolic or similar form so that the radar beam, which propagates upward from thereflector 16 in diverging directions, will at a second reflection become plane-parallel and directed vertically downward in thepipe 19. Thereflector 17 can also comprise aplastic plate 20, which is metallized on the portion of its upper side that is radially outward of thehorn 15, so that the whole of this portion of theplate 20 is covered by a metal film 21 (see the cross-section in Fig. 5). On the underside of theplastic plate 20, except for its central portion corresponding to the diameter of the horn, there is a printed conductor pattern consisting of spiral-form leads 22 that can be as closely spaced as the radial leads 18 on thelower reflector 16. The lead pattern together with the thickness of the plate (about 0.25 A in the actual dielectric) has the characteristic that an electromagnetic wave that has its E-vector perpendicular to the spirals is reflected with 180° lag compared with a wave that has the E-vector parallel with the spirals. The spiral form of the leads is such that a tangent to each at every point on it forms an angle α = 45° to the radius from the center of the spiral pattern through the same point; hence, the ultimate result is that the E01 mode, by reflection downward, is transformed to an H01 mode, that is to say the electrical field now takes a peripheral direction. Other, undesired modes of the radiation are at the same time reflected away. Thereflector 17 can be combined with the primary radiator 15, as shown in Fig. 2. 0162821 - The H01 mode so produced by the mode generator in propagating downward will go through the
lower reflector 16, and since the field of the Hal mode has the above mentioned direction the signal is not significantly influenced when it passes theleads 18 that extend perpendicular to the field and the shell that supports them. The microwave signal thereafter continues downward through thecistern pipe 7 to be reflected by the liquid surface when it meets the same and be returned to theantenna 15 and the coaxial cable 13. The echo signal is conducted by the cable to a receiver in theelectronic unit 14, where there takes place in a conventional manner a mixing of the transmitted and received signals, whereupon a determination of the material level takes place based upon the travel time, that is, the distance to thesurface 10. - During the upward travel of the echo signal through the
pipe 7, by reason of thehole 9, a part of its power will be converted to propagation modes other than the dominant H01 mode, and these will be returned in part to thelower reflector 16. Theradial grating 18 on this will however prevent these false echoes from propagating farther and reaching the interior of theantenna 15. The reflector thus functions in this respect as a mode filter. - The invention is not limited to the embodiment here shown and described. In an alternative embodiment the
reflector 17 can comprise a metallic surface with corrugations in the form of a spiral pattern as described above. In another embodiment the mode generator can comprise, instead of thereflectors pipe 7 can be employed. - A measuring system according to the illustrated or modified construction is preferred when the invention is applied to large tanks or cisterns where there can be employed as a waveguide an existing pipe with a diameter of 0.2 - 0.5 m. In a smaller pipe it is possible to employ as a mode generator a conventional HO1 - H11 transition, for example a Marie transition, in combination with a conical diameter adapter, but because of the requirement for mode suppression such a combination becomes very long (many meters) for many practical cases that are of interest. A certain improvement can be obtained with a non- conical funnel such as is shown in "State of the Waveguide Art" in Microwave Journal, December, 1982. In certain cases a funnel can offer a practical solution in combination with H01 as the dominant propagation mode, provided that the funnel can be hung down in the pipe. The length is then a lesser disadvantage, and through the special characteristics of the H01 mode the requirement for matching form between the pipe and the funnel becomes moderate.
Claims (11)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8402247A SE441306B (en) | 1984-04-25 | 1984-04-25 | SET AND DEVICE FOR SEATING NIVAN IN A CONTAINER CONTAINING FLUID MATERIAL |
SE8402247 | 1984-04-25 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0162821A1 true EP0162821A1 (en) | 1985-11-27 |
EP0162821B1 EP0162821B1 (en) | 1988-03-30 |
Family
ID=20355663
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP85850132A Expired EP0162821B1 (en) | 1984-04-25 | 1985-04-18 | Method and apparatus for measuring the level of a fluent material in a container |
Country Status (17)
Country | Link |
---|---|
US (1) | US4641139B1 (en) |
EP (1) | EP0162821B1 (en) |
JP (1) | JPS6128825A (en) |
KR (1) | KR930010470B1 (en) |
AU (1) | AU578279B2 (en) |
BR (1) | BR8501945A (en) |
DE (1) | DE3562053D1 (en) |
DK (1) | DK160374C (en) |
ES (1) | ES8607536A1 (en) |
FI (1) | FI73836C (en) |
HR (1) | HRP921001A2 (en) |
IN (1) | IN164742B (en) |
MX (1) | MX158252A (en) |
NO (1) | NO159962B (en) |
SE (1) | SE441306B (en) |
SI (1) | SI8510699A8 (en) |
YU (1) | YU46369B (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4404745A1 (en) * | 1994-02-15 | 1995-08-17 | Grieshaber Vega Kg | Level measurement arrangement for bulk material or liq. |
DE4407823A1 (en) * | 1994-03-09 | 1995-09-14 | Grieshaber Vega Kg | Level measurement appts. |
WO1998057392A1 (en) * | 1997-06-11 | 1998-12-17 | Saab Marine Electronics Ab | Horn antenna |
US7872610B2 (en) | 2005-11-24 | 2011-01-18 | Vega Grieshaber Kg | Metallised plastic antenna funnel for a fill level radar |
WO2012089356A1 (en) * | 2010-12-30 | 2012-07-05 | Rosemount Tank Radar Ab | High frequency mode generator for radar level gauge |
EP2796840A1 (en) * | 2013-04-24 | 2014-10-29 | VEGA Grieshaber KG | Mode converter for fill level radar |
Families Citing this family (34)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE461179B (en) * | 1989-02-08 | 1990-01-15 | Saab Marine Electronics | DEVICE FOR Saturation of the level of a fluid present in a container |
SE466519B (en) * | 1989-04-10 | 1992-02-24 | Saab Marine Electronics | DEVICE FOR Saturation of the level of a fluid present in a container |
FR2650080B1 (en) * | 1989-07-20 | 1991-11-08 | Materiel Auxil Signalisat Cont | DETECTOR FOR THE PRESENCE OF A COMPOSITE GUIDE OF ELASTIC WAVES |
WO1991019171A1 (en) * | 1990-06-05 | 1991-12-12 | Australian Coal Industry Research Laboratories Limited | Fluid level detector system and apparatus |
US5474198A (en) * | 1992-07-29 | 1995-12-12 | Saab-Scania Ab | Stillpipe sealing device |
DE4233324C2 (en) * | 1992-10-05 | 1996-02-01 | Krohne Messtechnik Kg | Process for measuring the level of a liquid in a container according to the radar principle |
US5406842A (en) * | 1993-10-07 | 1995-04-18 | Motorola, Inc. | Method and apparatus for material level measurement using stepped frequency microwave signals |
JP2655306B2 (en) * | 1993-10-19 | 1997-09-17 | 株式会社ワイヤーデバイス | Liquid level indicator |
US5440310A (en) * | 1994-02-14 | 1995-08-08 | Motorola, Inc. | Bandwidth synthesized radar level measurement method and apparatus |
US5495218A (en) * | 1994-04-20 | 1996-02-27 | Thermo Instrument Controls Inc. | Microwave waveguide seal assembly |
US5703289A (en) * | 1995-02-01 | 1997-12-30 | Magnetrol International, Inc. | Microwave transmitter housing |
US5614831A (en) * | 1995-02-13 | 1997-03-25 | Saab Marine Electronics Ab | Method and apparatus for level gauging using radar in floating roof tanks |
EP0887658B1 (en) * | 1997-06-27 | 2004-08-25 | EADS Deutschland GmbH | Radar level gauge |
DE19810601A1 (en) * | 1998-03-12 | 1999-09-16 | Daimler Benz Aerospace Ag | Arrangement for level measurement |
EP0947812A1 (en) * | 1998-03-28 | 1999-10-06 | Endress + Hauser GmbH + Co. | Microwave operated level gauge |
DE10010713B4 (en) * | 2000-03-04 | 2008-08-28 | Endress + Hauser Gmbh + Co. Kg | Level measuring device for transmitting and receiving broadband high-frequency signals |
DE10040943A1 (en) * | 2000-08-21 | 2002-03-07 | Endress Hauser Gmbh Co | Device for determining the level of a product in a container |
DE10109453A1 (en) * | 2001-02-27 | 2002-09-26 | Endress & Hauser Gmbh & Co Kg | Device for determining and / or monitoring the level of a product in a container |
SE0102881D0 (en) * | 2001-08-30 | 2001-08-30 | Saab Marine Electronics | radar Level Meter |
SE0103816D0 (en) * | 2001-11-16 | 2001-11-16 | Saab Marine Electronics | Slot antenna |
EP1422503B1 (en) * | 2002-11-20 | 2016-04-27 | Rosemount Tank Radar AB | Apparatus and method for radar-based level gauging |
JP4695394B2 (en) * | 2002-11-20 | 2011-06-08 | ローズマウント タンク レーダー アクチボラゲット | Liquid level measurement apparatus and measurement method using radar |
US6759977B1 (en) * | 2002-12-20 | 2004-07-06 | Saab Marine Electronics Ab | Method and apparatus for radar-based level gauging |
US6795015B2 (en) | 2003-01-29 | 2004-09-21 | Saab Rosemount Tank Radar Ab | Bottom reflector for a radar-based level gauge |
US7113125B2 (en) * | 2004-12-16 | 2006-09-26 | International Business Machines Corporation | Method for measuring material level in a container using RFID tags |
DE102006013923A1 (en) * | 2006-03-25 | 2007-09-27 | Festo Ag & Co. | Microwave position measuring device for e.g. fluid technical linear actuator, has microwave antenna arrangement formed in mode, with which electrical field of microwaves at cross section inner circumference of waveguide is zero |
US20080100501A1 (en) * | 2006-10-26 | 2008-05-01 | Olov Edvardsson | Antenna for a radar level gauge |
US8350752B2 (en) * | 2010-07-09 | 2013-01-08 | Rosemount Tank Radar Ab | Radar level gauge system with bottom reflector and bottom reflector |
DE102011106568B4 (en) * | 2011-06-28 | 2013-09-19 | Krohne Messtechnik Gmbh | Float to indicate a level |
US9325077B2 (en) * | 2013-11-12 | 2016-04-26 | Rosemount Tank Radar Ab | Radar level gauge system and reflector arrangement |
DE102016105419B4 (en) * | 2016-03-23 | 2017-11-02 | Endress + Hauser Gmbh + Co. Kg | Method for determining a pipe inside diameter of a still pipe by a level gauge |
US10725160B2 (en) * | 2017-04-07 | 2020-07-28 | Rosemount Tank Radar Ab | Non-invasive radar level gauge |
US10775211B2 (en) | 2017-05-03 | 2020-09-15 | Quest Automated Services, LLC | Real-time vessel monitoring system |
EP3693711B1 (en) * | 2019-02-11 | 2021-06-02 | VEGA Grieshaber KG | Radar measurement device with plane convex lens |
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US3572119A (en) * | 1969-08-07 | 1971-03-23 | Bendix Corp | Fluid quantity indicating device |
US3995212A (en) * | 1975-04-14 | 1976-11-30 | Sperry Rand Corporation | Apparatus and method for sensing a liquid with a single wire transmission line |
US4359902A (en) * | 1980-07-31 | 1982-11-23 | Lawless James C | Liquid level gauge |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
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FR2496274A1 (en) * | 1980-12-12 | 1982-06-18 | Trt Telecom Radio Electr | FREQUENCY-MODIFIED MAIN-WAVE RADAR DISTANCE DISTANCE MEASURING METHOD, APPARATUS FOR IMPLEMENTING THE METHOD, AND APPLICATION TO THE ACCURATE DETERMINATION OF THE LIQUID LEVEL IN A RESERVOIR |
US4489601A (en) * | 1983-07-18 | 1984-12-25 | Sperry Corporation | Apparatus and method of measuring the level of a liquid |
US4566321A (en) * | 1985-01-18 | 1986-01-28 | Transamerica Delaval Inc. | Microwave tank-contents level measuring assembly with lens-obturated wall-opening |
-
1984
- 1984-04-25 SE SE8402247A patent/SE441306B/en not_active IP Right Cessation
-
1985
- 1985-04-18 EP EP85850132A patent/EP0162821B1/en not_active Expired
- 1985-04-18 DE DE8585850132T patent/DE3562053D1/en not_active Expired
- 1985-04-19 FI FI851556A patent/FI73836C/en not_active IP Right Cessation
- 1985-04-19 AU AU41428/85A patent/AU578279B2/en not_active Expired
- 1985-04-20 IN IN300/MAS/85A patent/IN164742B/en unknown
- 1985-04-22 NO NO851600A patent/NO159962B/en unknown
- 1985-04-22 US US06725621 patent/US4641139B1/en not_active Expired - Lifetime
- 1985-04-24 MX MX205072A patent/MX158252A/en unknown
- 1985-04-24 DK DK182385A patent/DK160374C/en not_active IP Right Cessation
- 1985-04-24 ES ES542528A patent/ES8607536A1/en not_active Expired
- 1985-04-24 BR BR8501945A patent/BR8501945A/en not_active IP Right Cessation
- 1985-04-25 KR KR1019850002790A patent/KR930010470B1/en not_active IP Right Cessation
- 1985-04-25 JP JP8986885A patent/JPS6128825A/en active Granted
- 1985-04-25 SI SI8510699A patent/SI8510699A8/en unknown
- 1985-04-25 YU YU69985A patent/YU46369B/en unknown
-
1992
- 1992-10-02 HR HRP921001AA patent/HRP921001A2/en not_active Application Discontinuation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US3572119A (en) * | 1969-08-07 | 1971-03-23 | Bendix Corp | Fluid quantity indicating device |
US3995212A (en) * | 1975-04-14 | 1976-11-30 | Sperry Rand Corporation | Apparatus and method for sensing a liquid with a single wire transmission line |
US4359902A (en) * | 1980-07-31 | 1982-11-23 | Lawless James C | Liquid level gauge |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4404745A1 (en) * | 1994-02-15 | 1995-08-17 | Grieshaber Vega Kg | Level measurement arrangement for bulk material or liq. |
DE4407823A1 (en) * | 1994-03-09 | 1995-09-14 | Grieshaber Vega Kg | Level measurement appts. |
WO1998057392A1 (en) * | 1997-06-11 | 1998-12-17 | Saab Marine Electronics Ab | Horn antenna |
US6278411B1 (en) | 1997-06-11 | 2001-08-21 | Saab Marine Electronics Ab | Horn antenna |
US7872610B2 (en) | 2005-11-24 | 2011-01-18 | Vega Grieshaber Kg | Metallised plastic antenna funnel for a fill level radar |
WO2012089356A1 (en) * | 2010-12-30 | 2012-07-05 | Rosemount Tank Radar Ab | High frequency mode generator for radar level gauge |
US8842038B2 (en) | 2010-12-30 | 2014-09-23 | Rosemount Tank Radar Ab | High frequency mode generator for radar level gauge |
EP2796840A1 (en) * | 2013-04-24 | 2014-10-29 | VEGA Grieshaber KG | Mode converter for fill level radar |
WO2014173951A1 (en) * | 2013-04-24 | 2014-10-30 | Vega Grieshaber Kg | Mode converter for fill level radar |
KR20160002676A (en) * | 2013-04-24 | 2016-01-08 | 베가 그리이샤버 카게 | Mode converter for fill level radar |
US10078001B2 (en) | 2013-04-24 | 2018-09-18 | Vega Grieshaber Kg | Mode converter for filling level radar |
CN105229430B (en) * | 2013-04-24 | 2019-06-18 | Vega格里沙贝两合公司 | Mode converter for fill level radar |
Also Published As
Publication number | Publication date |
---|---|
FI73836C (en) | 1987-11-09 |
SI8510699A8 (en) | 1996-08-31 |
MX158252A (en) | 1989-01-17 |
AU4142885A (en) | 1985-10-31 |
HRP921001A2 (en) | 1994-04-30 |
BR8501945A (en) | 1985-12-24 |
JPS6128825A (en) | 1986-02-08 |
SE441306B (en) | 1985-09-23 |
DK182385A (en) | 1985-10-26 |
SE8402247D0 (en) | 1984-04-25 |
KR930010470B1 (en) | 1993-10-25 |
AU578279B2 (en) | 1988-10-20 |
NO851600L (en) | 1985-10-28 |
ES8607536A1 (en) | 1986-05-16 |
IN164742B (en) | 1989-05-20 |
DK160374B (en) | 1991-03-04 |
DK160374C (en) | 1991-08-12 |
YU46369B (en) | 1993-10-20 |
EP0162821B1 (en) | 1988-03-30 |
DE3562053D1 (en) | 1988-05-05 |
US4641139B1 (en) | 1998-04-14 |
FI851556A0 (en) | 1985-04-19 |
KR850007299A (en) | 1985-12-02 |
FI73836B (en) | 1987-07-31 |
US4641139A (en) | 1987-02-03 |
YU69985A (en) | 1988-08-31 |
FI851556L (en) | 1985-10-26 |
DK182385D0 (en) | 1985-04-24 |
NO159962B (en) | 1988-11-14 |
ES542528A0 (en) | 1986-05-16 |
JPH0423726B2 (en) | 1992-04-23 |
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